FAKE SIGNATURE OF REGISTRAR ON REGISTRY OF FLAT

I have a query regarding My flat Registry. I registered my flat in May 2016 through my Builder and has a loan against it in Axis bank. Now in July-17, I transfer my loan to HDFC bank, a lawyer from HDFC bank saw that in my Registry there is no sign of Registart on the back side of the last page in the Red color pen (although there are a proper sign on all the relevant pages). I reached to Registrar Office and came to know The Registart has been retired now and also they told me that Registry doesn't contain Witness's Photos that's why Registrar might leave his Signature. So I reached to the builder and their lawyer told me they would get it signed of the Registrar for me by going his home. Today I received my Registry paper signed. Now what should I do, should I go to registrar office to provide them the updated copy so they could upload my Registry paper? Is it mandatory? The second concern is: if the builder itself did fake Signature of Registrar, then what should I do now?